Electrical connector body and cap construction with improved conductor securing means



Feb. 6, 1962 v. R. DESPARD 3,020,516

ELECTRICAL CONNECTOR BODY AND CAP CONSTRUCTION WITH IMPROVED CONDUCTORSECURING MEANS Filed April 25, 1958 2 Sheets-Sheet 1 56 Ii, A2} INVENTOR57 I i1: T VICTOR R. 055mm 52 ATTORNEYS Feb. 6, 1962 v. R. DESPARD3,020,516

ELECTRICAL CONNECTOR BODY AND CAP CONSTRUCTION WITH IMPROVED CONDUCTORSECURING MEANS Filed April 25, 1958 2 Sheets-Sheet 2 57 FIG. /2

INVENTOR VICTOR l7. OE'SPARD rfi uv.

ATTORNEYS States atent 3,020,516 Patented Feb. 6, 1962 York Filed Apr.25, 1958, Ser. No. 730,839 11 Claims. (Cl. 339-101) This inventionrelates to electrical connector body and cap construction and toimproved conductor connecting and securing means therefor.

It is one of the general objects of the present invention to providenovel and improved electrical connector and cap construction.

Another general object of the invention consists in the provision ofnovel and improved combination conductor connecting and securing meanswhich combine the functions of the usual screw terminals and strainrelief devices.

More particularly the invention comprises connector body and capconstruction in which each body and cap part includes a terminal base ofinsulation having connector contacts extending from one face thereof, aconductor connecting means buried in the base for and connected to eachcontact and a resilient, flexible shell enclosing the sides and oppositeface of said base and closely fitting the cabled conductors leading fromthe connecting means.

An important object of the invention comprises the arrangement of aseparate flexible and elastic sleeve adapted to partially encase theshells of a mated cap and connector body to secure them together andexclude moisture from the contacts and conductors thereof.

A specific feature of the connector sleeve includes a sectionintermediate the ends thickened to provide inner stop shoulders forcentralization on the mated units and to provide thin end sections whichcan be turned back for ease of application over or removal from therubber like shells on the individual units.

Another important object of the invention resides in the combinationwire connector and conductor grip devices embedded in the bases andactuated each by a radially directed screw normally covered by theresilient shell.

Specific features of-thecombinationconnector and grip include a singlescrew for each threaded into a terminal plate having a tang passingthrough the block to connect to and mount one of the connector contacts,said screw having a tapered pin at its end adapted to penetrate theinsulation of a stranded conductor and make electrical contact with thestrands thereof and carryingbehind said pin a clamp member adapted toengage the insulation of the stranded conductor above and below the pinengaged area and press it tightly into and against the walls of a groovein the material of the base to resist withdrawal in the direction of theconductor length, the .arrangement being such that the clamping actiontakes place'simultaneously with the vpin penetration.

A still further object of the invention resides in the arrangement ofthe conductor confining grooves in a base to face radially outwardlyfrom approximately the center thereof so that the several conductors ofa multiwire cable are close together and are mutually supporting whenurged toward the center by said clamp members.

Other and further objects and features of the invention will be moreapparent to those skilled in the art upon a consideration of thefollowing specification and the accompanying drawings wherein isdisclosed a single exemplary embodiment of the invention with theunderstanding that such changes and modifications may be made, thereinas fall within the scope of the appended claims without departing fromthe spirit of the invention.

In said drawings:

FIGURE 1 is an elevation of a complete connector assembly of body andcap, with connecting sleeve and conductor cable sections shown;

FIGURE 2 is an exploded view of the basic three components of theconnector assembly of FIGURE 1 showing the connector sleeve with rolledback lips;

FIGURE 3 is a face view of the connector body portion with the resilientcover in place but with the contact cover block removed;

FIGURE 4 is a rear face view of the contact cover block; 7

FIGURE 5 is a face viewof the connector cap shown with the resilientcover in place;

FIGURE 6 is a longitudinal central section through a connector bodytaken on line 6 6 of FIGURE 3 and showing the base and contact coverblock in elevation;

FIGURE 7 is a longitudinal-central section through the resilient,flexible cover sleeve;

FIGURE 8 is a view similar to FIGURE 6 but taken on line 88 of FIGURE 5of the cap;

FIGURE 9 illustrates in longitudinal central section the sleeve mountedon the connector body and having its free lip rolled back to permitconnecting the cap to the body;

FIGURE 10 is an enlarged side elevation of the con ector cap with itselastic shroud removed and showing the wire clamping screws; FIGURE 11is a front view of the cap showing the clamping screws extended;

FIGURE 12 is a rear view of the cap illustrating the conductor grooves,clamps and penetrating pins arranged to accept conductors for-fastening;

FIGURE 13 is a face view, on a still larger scale of the conductor clampand associated parts taken on line 13-13 of FIGURE 12;

FIGURE 14 is a section taken on line'14-14 of FIG? URE 13 and showingboth the retracted (solid line) position and the clamping (dotted line)position of the conductor clamp and actuating screw; and

FIGURE 15 is a view similar to FIGURE 12 butshowing the individualconductors of a cable connected electrically to the blades of andclamped to the insulation base of the cap.

Attachment plugs or caps and their cooperating com ponents, connectorbodies, are available in an amazing number of sizes, styles, capacities,types and the like, making the required stock of manufacturers and dis,-tributors run to well over different items. The. devices vary in thenumber of terminals, blades or contacts per unit, in the arrangementsfor polarization or nonpolarization, the use of grounding terminals,special'locking arrangements for preventing separation of the cap andconnector body under strain, and the presence or absence of strainrelief clamps for preventing pull on the cables orconductors from beingtransferred to the wire' connecting means or terminals. When consideringtwo wire, three wire, four, wire and other combinations, with or withoutgrounding l terminals, polarized and non polarized, and so on, the totalnumberof sizes and combinations offered by some manufacturers runs tomore than styles, making the cost ofcarrying a full stock prohibitiveand leading to the occurrence of errors in ordering and delivering.

The present invention proposes a simplification whereby approximatelytwenty-five diiferent devices will perform the functions heretoforecarried out by one hundred with no reduction whatsoever in currentcarrying ability, strain relief, waterproofness and'the like. At thesame time, the facility of .wiring the devices is enhanced to such anextent that the time savingfmayrun as much as any to ninety percent ofthat normally consumed. At the same time, the construction issimplified, the number of parts materially reduced and the size andweight curtailed.

Referring now to the drawings, and particularly to FIGURES l to 9inclusive, it will be noted in the first of these figures that cables20, each of the multi-conductor type are connected in a separable mannerby a connector body 21, and cap 22. Each of these components includes acylindrical base, 24 for the connector body and 25 for the cap, eachhaving plane top and bottom surfaces normal to the axis of the cylinder.The front face of base 24 is seen in FIGURE 3, at 27 supporting thegrounding contact 28 and the two conductor contacts 22 and 30, in a twowire and grounding style of connector body which is used herein asrepresentative. Each of these contacts is fitted with an integral foot28', 29' and 30', set in base 24 flush with the surface 27 as seen, andpreferably arranged so that the feet reach to the edge of the cylinder.

In a like manner base 25 of cap 22 has a front face 32 into which arerecessed, somewhat deeper than in the case of base 24, the feet of plugblades 33 and 34 and of the U-shaped grounding plug prong 35, spacedthereon to mate with the corresponding female contacts on block 24.

To complete the connector body, the contacts are housed in a cylindricalinsulation block 37, best seen in FIGURES 6 and 9 in side elevation andin rear elevation in FIGURE 4, where the chambers 39,40 and 41,respectively, extending axially partially through the insulation aresized to loosely house the contacts 28, 29 and 30, and each has a smallopening, 42, 43 and 44 respectively through the front face, sized toloosely receive the plug and prong blades, as seen in FIGURE 5. Theblock 37 is of less diameter than the base 24, as clearly indicated inFIGURE 9, providing an annular area 46 where the larger base extends outbeyond the smaller block. A corresponding area is provided on the cap byhaving its base 25 slightly longer than the one in the connector bodyand grooved peripherally on its contact-blade carrying face to providethe annular area 47 corresponding in depth and width to 46 and leavingthe same length of exposed cylindrical side wall.

In this manner the insulation base parts 24 and 25 of the cap andconnector body are identically sized in length to receive each a similarwaterproof cover or sheath 50 of flexible, resilient, material such assuitable natural or synthetic rubber, preferably one resistant to oiland similar liquids. Such a cover includes a cylindrical, tubularportion 52 sized to closely engage the cylindrical walls of block 24 or25 and of just the same length. At its outer end it is provided with aninturned lip or annular ring 53 to overlap the annular area 46 or 47previously described and have its inner facing edges 54 closely engagedagainst the cylindrical wall of contact cover block 37. When applied tothe cap body 25 the lip fits in the annular area 47 previously referredto and its edge 54 engages against the smaller diameter shortcylindrical portion 55 as seen in FIGURE 8.

The cover has at the rear edge of the cylindrical portion 52 an integralannulus 56 spaced from lip 53 just sufficiently to accommodate thelength of block 24 or 25 between its annular reduced portion 47 and therear face. The radial extent of part 56 is somewhat greater than that of53 and attached integrally to its inner periphery is the frusto-conicalor cup-like, portion 57 having at its outer end the annular member 58centrally perforated as at 59 to closely engage over the sheath of cable20 to form a water and dust tight joint. This opening is small enough toprovide the desired tight fit with the cover of the smallest cableintended to be used with the unit, and, because of its resilience can bestretched over one many sizes larger, thus accommodating any of thecable diameters required to house conductors of a size and number usablewith the connectors.

It will be appreciated that the flexible covers are accurately sized totightly fit over block 24 or 25 so that when placed in position theycompletely house all but the small circular area on the face of theblock which carries the various types of contacts. They protect theterminals, which will be later described, shield the insulation baseagainst shocks and provide a finished appearance as well as a uniformexposed surface for receiving the connecting sheath shown at 60 inFIGURE 1, in section in FIG- URE 7, with both lips rolled back in FIGURE2, and applied to the connector body with one lip rolled back in FIGURE9. This sleeve comprises a straight outer-walled tube of resilientflexible material such as that used in the covers, having a thick centerportion as shown at 61, the inner diameter thereof being such as to fiteasily over block 37, comprising the contact cover of the connectorbody, and having a length between shoulders 62 to extend from the lip 53of sheath 50 to the outer face of block 37. At each end the thickenedportion is provided with a thin lip section 64, the reduction inthickness being entirely from the interior leaving thin walls 65 whichcan be rolled or turned back, as shown at 66 in FIGURE 2, over the morerigid central section to facilitate the application to the covers of theconnector body and cap.

Such attachment is effected by sliding the sleeve over block 37 until ashoulder 62 abuts the outer face of lip 53 and then rolling lip 64 overthe cylindrical portion 52 of sheath 50, to the position illustrated inFIGURE 9, effecting a water and dirt tight connection but leaving theremaining lip turned back as at 62 for connection of the cap to theconnector body in the usual manner by inserting the prong and bladesthereon into the contacts housed in block 37. Then lip 64 is rolled overthe cover of the cap so that the assembly appears symmetrical as seen inFIGURE 1. In each instance the lips 64 are substantially stretched overthe covers 50 as seen in FIG- URE 1, which operation is facilitated bythe rolling process and a water and dust-tight connection insured. Thusno liquid or dirt can get between the cap and connector body nor nonebetween the sheath of the cable 20 and the covers 50, whereby completeprotection is offered against moisture and dirt or damage by dropping orengagement with hard objects.

FIGURES 10 to 15 inclusive illustrate the wire attaching features of thecap and connector body and since they are identical in construction andoperation they have been illustrated only in connection with the cap tosimplify the showing.

It is highly desirable that the individual conductors from the cable bespread as little as possible and enter the base block for connection tothe terminals in a nearly axial direction. This is facilitated by thearrangement illustrated in FIGURES l2 and 15 where the rear face of thebase is shown as intersected by a recess 65 for each conductor,identical in size and shape and symmetrically arranged about thecylinder axis. Each recess extends not quite to the center, where it hasan arcuate wall 66 of somewhat less than extent and of a radius which isa mean of those of the various size individual conductors to be usedtherewith measured with their individual insulation sheaths.

In general a cap or connector body of the so-called l0 ampere size orcapacity is arranged to accept a 16 or 18 size wire, a 15 ampere size 16and 14 wire, 20 ampere size 14 and 12 wire and 30 ampere size 12 and 10wire. The carrying capacity of these size wires are commensurate withthe current conducting capacity of the contacts in the caps andconnector bodies.

Each recess 65 includes a pair of plane walls 67 which merge arcuatewall 66 and include an angle of approximately 50 between them. At theintersection of these and the arcuate wall with the rear face of block25 chamfers 68 are provided to facilitate the entrance of multistrandconductors of the type which must be used with this construction, and toeliminate any possible abrasion of the insulation.

Parallel walls 69 slightly off-set at 70 form extensions of theV-channel just described and extend the chamber through the cylindricalwall of the base byway of parallel walls 72 somewhat wider spaced apartthan walls 69 and transverse grooves 73 are arranged as the junction ofthe sets of parallel walls and extends clear to the flat bottom 74 ofthe chamber. This bottom does not extend through the cylindrical basewall but stops short of it. FIGURE shows the U-shaped opening 71 throughthis wall.

Fitted in the cross channels 73 is a sturdy-terminal plate 75 ofconductive metal extending against the bottom 74 but terminatingconsiderably short of the outer face of the base as seen in FIGURE 14.It has a nearly fiat central section and inwardly offset ends 76 whichfit in the channels previously defined. On the horizontal, but slightlyabove the vertical center, the plate is drilled normally and the bore isinternally threaded to closely receive the threads of the shank of screw78 preferably having a filistcr head 79. V v

The end of screw 78 is reduced in diameter and then provided with atapered or conical tip 80 at such a distance from the under face of head79 that when this latter bears against plate 75 the tip 80 is just inengagement .with arcuate surface 66 as seen dotted in FIGURE 14. Theconical tip 80 is of a length approximately the outer diameter of thelargest conductor which it will be required to penetrate. The tipsprings from reduced diameter portion 81 terminated by a radial shoulderand extends through a loosely fitting bore in the square center sectionof clamping plate 82 which is held in position thereon by swaged collar83. The plate 82 is provided with integral arms, 84 at the top and 85 atthe bottom, which are forwardly offset as seen in FIGURE 14 so that aplane through their forward faces extends through the conical tip 80 ofthe screw somewhere intermediate its length. The lower arm 85 is longerand its outer end fits loosely in a radial channel or groove 86 in thebottom wall of the chamber, whose sides and bottom are parallel to theaxis of the screw whereby the clamping plate is held against rotationwith the screw.

Screw 78 is in electrical engagement with terminal plate 75' and thelatter is connected to the foot of its corresponding blade or contactelement by means of an integral tang 88, best seen in FIGURES l0 and 14.This passes through an appropriate passage in the base 25, and sinceeach chamber 65 is directly above the recess for the foot'of one of theconnector blades, it enters this recess and passes through an aperture89 in the foot and is swaged over as shown at 90 in FIGURE 11,completing the electrical connection between the two parts andmechanically holding each in its chamber or recess.

The facility for wiring the present device is one of its importantpoints. All that is necessary is to cut the cable oif squarely, pass itfirst through hole 59 in flexible sheath 50, which has been removed fromthe base, and then remove the outer covering and the jute fillers, whichform the round shape of the cable, for a length of about onehalf inch,after which the still insulated, individual, stranded conductors areinserted each in their respective compartments 65, the screws havingbeen previously withdrawn to nearly the positions indicated in FIGURE12. The conductors are pushed in until they bottom in their respectivechambers and the screws are now tightened down. The respective cavitiesare shaped to center various diameters of wire and as the contact screwis threaded down the point begins to penetrate the insulation, centeringthe wire in the apex of the V. The point continues to pierce theinsulation and spread the stranded group of conductors as it entersbetween them. The curved backing for the wire prevents the group ofconductors from flattening even though at this time the strain relievingarms 84 and 85 are already beginning to press on the surface of theinsulation of the wire. This tends to compact the assembly and packs theindividual strands tightly around the point of the screw assuringadequate electrical connection andcurrent flow.

The combination of the pointed terminal screw and automatic clampcarried by the screw in the V-shaped cavity, insures practically perfectassembly and contact. The screw is run up until the under surface of itshead locks tightly against the outer face of terminal plate 75 wherefriction insures against it being vibrated loose under anycircumstances. The screw length may be ad justed so that the pointenters slightly into the insulating material further adding to thestrain relief action of the pressure arms which have flattened the wireto some extent above and below the entrance point of the conical screwtip as seen in FIGURE 14 (dotted). When the screw heads are tightenedagainst the terminal plates they do not extend beyond the cylindricalsurface of base 25, as seen in FIGURE 15, Where the three conductors areshown at 92 as being formed of a plurality of relatively thin strands ofcopper wire surrounded and tightly compact-ed by the extruded plasticinsulation cover 93. As is common in such constructions the twistedbundle of stranded wires is first bound together by a single layer ofmultiple threads arranged helically about it to maintain the shape ofthe bundle while the plastic insulation is extruded in position.

It will be obvious that the single operation of turning in one screw,per conductor, provides not only for male ing careful and adequateelectrical contact therewith but also provides for clamping theconductor in two positions, one on either side of the penetrating point,to produce effective strain relief without the need for clamps or thelike for the main body of the cable.

After the individual conductors have been secured in position as justdescribed the sheath 50 is advanced along the wire and stretched overthe base 25 until it achieves the position illustrated in FIGURE 8 whenthe device is ready for use. For the connector body section theoperation is identical, right to the final assembly of the sheath orcover 50. Thereafter connecting sleeve 60 may be applied to theconnector body section as described in connection with FIGURES 2, 6 and7, and the circuit can now be completed between the two sections ofcable by bringing the connector body and cap together in the usualmanner to engage the blades and contacts, and then rolling the sleeveover if it is desired to effect a watertight connection which cannotreadily be pulled apart by strain.

It will be obvious how the invention is adapted to handle a greater or aless number of individual conductors in accordance with the specificconstruction of the cap and connector body for any particular usage.

I claim:

1. In an electric connector device for use with various sized cables,each having a plurality of individually insulated stranded conductors incombination, a rigid cylindrical base of insulation material havingcontacts carried thereby, one for each conductor and extending from oneend thereof, a recess opening through the opposite end of the base andpartially through the side wall thereof for each contact, each recesshaving side walls converging to a fillet adjacent the axial center ofsaid base, a rigid terminal plate electrically connected to each contactand having its ends inserted axially into channels in the walls of thecorresponding recess so as to partially close the side wall openingthereof, means mounted by said plate to electrically connect one of saidstranded conductors to said plate and mechanically hold it tightly intothe recess fillet and axially of the base, and a flexible resilientcover for said base includin a tubular sleeve closely engaging the sidewall of said base, covering said terminal plates and recess openings inthe cylindrical wall, having an integral annulus partially covering therecess openings in the said end wall and an integral axial sleeveadapted to 7 engage the cable and hold it in substantial alignment withthe conductors in the fillets.

2. The device defined in claim 1 in which the means mounted by saidplate is a terminal screw which extends radially of the base througheach terminal plate toward the fillet beneath it, and means on eachscrew to penetrate the insulation of a multistrand conductor wire ofsaid cable and electrically contact the wires thereof.

3. The device defined in claim 2 in which each screw is fitted behindthe insulation penetrating means with arm means laterally extendingtherefrom and independent of the penetrating means to engage andautomatically clamp the conductor against a recess wall to relieve thescrew wire connection of strain.

4. The device defined in claim 3 in which said means is a clamp bararranged to engage the insulation cover of the multistrand conductor attwo positions spanning the said connection.

5. The device as defined in claim 1 in which each terminal plate hasends engaged in axially disposed slots in the wall of its recess sospaced radially that the said cover en gages the outer end of the screwto prevent undesired loosening.

6. A combined electrical connector for a stranded conductor andmechanical attachment therefor including in combination, a base block ofrigid insulation material having a recess therein with converging wallsconnected by an arcuate wall of a curvature of the order of that of theinsulation covering of a stranded conductor for use therewith, means insaid block having a threaded hole therein with its axis directed towardsaid arcuate wall, a screw threaded in said hole having a pointed endfor advancement to penetrate the insulation and contact the strands ofsaid conductor, a plate swiveled on said screw behind said point, andarms on said plate positioned to engage the insulation of said conductorabove and below the screw end penetration to clamp it against saidarcuate wall.

7. The construction of claim 6 in which said arms have clamping surfacessubstantially parallel to the center of curvature of said arcuatesurface and lying in a plane intersecting said screw intermediate thelength of said pointed end.

8. The arrangement of claim 7 in which one wall of said recess has guidemeans parallel to the axis of said screw and means on one of said armscooperating there with to prevent rotation of said swiveled plate.

9. An electrical connector for attaching a stranded con ductor to aseparable contact, in combination, a substan tially cylindrical baseblock of rigid insulating material having flat ends parallel to eachother, contacts each having a foot on one end of said block, a recessfor each contact in the opposite end of said block opening also throughthe side of the block, a terminal plate for each recess mounted in slotsto position it nearly parallel to said side and at least partiallyclosing said opening, means integral with each plate extending throughsaid insulation and secured to the corresponding foot for mutual supporton said block and electrical connection, the inner side walls of eachrecess converging toward the block center at an acute angle, a filletconnecting said walls of each recess short of their intersection, and aradially disposed screw threadedly engaged in each terminal plate andhaving a pointed end and a head positioned to engage with said platejust as the point engages said fillet.

10. The device of claim 9 in which said screw point is conical and thescrew shank is reduced in diameter behind the point, a plate having acentral bore swiveled on said diameter and oppositely disposed arms onsaid plate offset toward said point to clamp a conductor against saidfillet on opposite sides of the area penetrated by said screw point.

11. The device of claim 10 in which one of said arms prevents the platefrom rotating with the screw, a groove in a wall of said recess parallelto said screw, the side walls of said groove engaging said one arm toprevent said rotation.

References Cited in the file of this patent UNITED STATES PATENTS791,603 Beau et a1. June 6, 1905 1,279,427 Peterson Sept. 17, 19181,874,334 Nero Aug. 30, 1932 1,949,596 Anderson Mar. 6, 1934 2,015,590Cavanagh et al a- Sept. 24, 1935 2,032,780 White Mar. 3, 1936 2,034,695Dougherty Mar. 24, 1936 2,419,683 Henschke Apr. 29, 1947 2,704,835Heller Mar. 22, 1955 2,758,291 Richards Aug. 7, 1956 2,789,276 HummelApr. 16, 1957 2,872,503 Winter Feb. 3, 1959 2,873,435 Hubbell Feb. 10,1959 FOREIGN PATENTS 316,917 Switzerland Dec. 15, 1956 524,140 GreatBritain July 31, 1940 705,121 France Mar. 3, 1931

